THE WHEELER SURVEY AND THEORETICAL TECTONICS: THE BASIN AND RANGE

From 1869 to 1879 Lieutenant G. M. Wheeler led the US Geographical Surveys West of the 100th Meridian. Before the Civil War the Corps of Topographical Engineers conducted numerous surveys, with civilian geologists and naturalists accompanying survey parties. Logistical requirements and native American resistance dictated military escorts for scientific parties; these broad reconnaissance efforts filled in geological outlines. Conditions after the Civil War reflected settling of the frontier and the rise of an independent scientific establishment, and led to four competing federal surveys. Wheeler’s survey marked the last attempt by the Corps of Engineers to maintain the surveying role of the topographical engineers with whom they merged in 1863. By the 1870’s scientists did not require the military to conduct research, and geologists did not enjoy army procedures. Wheeler’s best geologist, G.K. Gilbert, served only a few years with Wheeler, but ultimately did the best theoretical tectonic work of any federal survey. Only some Powell Survey work on the Colorado Plateau might compare in fundamental importance; the King and Hayden surveys continued the reconnaissance tradition of the pre Civil War surveys, and Hayden’s perceived lack of scientific rigor played a large role in his being passed over as first director of the USGS. Gilbert’s theoretical success stemmed from several factors: the fast Army pace forced accurately summarized observations of the big picture; the survey took him through some of the best geological terrain; and he was one of the best geologists ever. Gilbert accurately recognized the normal faults creating the Basin and Range, providing a second model for orogenic tectonics to complement folding. The nature of normal faulting in mountain formation remains a key research area of theoretical tectonics, with the current debate concerning the relative roles of high-angle versus low-angle faults in creating the landscape Gilbert first accurately described.